This invention is directed to a head or barrel for a drill which allows for drilling holes in a workpiece with a high degree of accuracy and is particularly adaptable to industrial drills.
The drilling of a hole to a desired depth in a workpiece has always presented a problem. Many solutions have been presented, including the fixing of a small ring or collar to the drill bit. For general work, this solution has been relatively satisfactory, but has certain drawbacks. An individual using the drill may set the collar at a desired position by use of a scale, but this does not permit a high degree of accuracy. Further, the collar rotates with the drill bit, so that, when the depth is reached and the collar impinges upon the workpiece, a scoring or marring of the finish results.
Another solution involves the provision in a drill head similar to that of the present invention of a multiplicity of internal barrels of different lengths. The surface against which the barrel abuts is fixed and the lengths of the barrels correspond to the depths to which the holes are to be drilled. This provides accuracy which is superior to that obtained by other drills, but requires disassembly of the drill head and the replacement of the drill bit and the barrel each time a hole of a different depth is to be drilled.
The present invention provides a means for overcoming the prior art disadvantages which incorporates an adjustable abutment means which permits the drilling of holes of a variety of depths to a degree of accuracy heretofore unobtainable with a hand-held drill.